This mini assignment kicked-off with replacing `pubsub` with `pep`,
but later transformed into something more.
The alterations and additions in this commit:
a) GeoLocation.
1) Add Documentation.
2) Add `EMPTY_GEO_LOCATION` to be used while
`stopPublishingGeoLocation()` is called.
b) Add GeoLocation IntegrationTest.
c) Add GeoLocation Listener.
d) GeoLocationManager.
1) Add Documentation.
2) Replace `pubsub` with `pep`.
3) Add methods to add-and-remove GeoLocationListeners.
4) Enable GeoLocation by default.
e) Add `package.info` for GeoLocation Integration Test.
340e186cf6